| 1092 |
|
a parallel BSDF surface may be |
| 1093 |
|
placed slightly less than the given thickness away from the front surface |
| 1094 |
|
to enclose the complex geometry on both sides. |
| 1095 |
+ |
The sign of the thickness is important, as it indicates |
| 1096 |
+ |
whether the proxied geometry is behind the <emph>BSDF</emph> |
| 1097 |
+ |
surface (when thickness is positive) or in front (when |
| 1098 |
+ |
thickness is negative). |
| 1099 |
|
<p> |
| 1100 |
< |
The second string argument is the name of the BSDF file, which is |
| 1101 |
< |
found in the usual auxiliary locations. |
| 1102 |
< |
The following three string parameters name variables for an "up" vector, |
| 1103 |
< |
which together with the surface normal, define the |
| 1104 |
< |
local coordinate system that orients the BSDF. |
| 1105 |
< |
These variables, along with the thickness, are defined in a function |
| 1106 |
< |
file given as the next string argument. |
| 1107 |
< |
An optional transform is used to scale the thickness and reorient the up vector. |
| 1100 |
> |
The second string argument is the name of the BSDF file, |
| 1101 |
> |
which is found in the usual auxiliary locations. The |
| 1102 |
> |
following three string parameters name variables for an |
| 1103 |
> |
"up" vector, which together with the surface |
| 1104 |
> |
normal, define the local coordinate system that orients the |
| 1105 |
> |
BSDF. These variables, along with the thickness, are defined |
| 1106 |
> |
in a function file given as the next string argument. An |
| 1107 |
> |
optional transform is used to scale the thickness and |
| 1108 |
> |
reorient the up vector. |
| 1109 |
|
<p> |
| 1110 |
< |
If no real arguments are given, the BSDF is used by itself to determine |
| 1111 |
< |
reflection and transmission. |
| 1112 |
< |
If there are at least 3 real arguments, the first triplet is an |
| 1113 |
< |
additional diffuse reflectance for the front side. |
| 1114 |
< |
At least 6 real arguments adds diffuse reflectance to the rear side of the surface. |
| 1115 |
< |
If there are 9 real arguments, the final triplet will be taken as an additional |
| 1116 |
< |
diffuse transmittance. |
| 1117 |
< |
All diffuse components as well as the non-diffuse transmission are |
| 1118 |
< |
modified by patterns applied to this material. |
| 1119 |
< |
The non-diffuse reflection from either side are unaffected. |
| 1120 |
< |
Textures perturb the effective surface normal in the usual way. |
| 1110 |
> |
If no real arguments are given, the BSDF is used by itself |
| 1111 |
> |
to determine reflection and transmission. If there are at |
| 1112 |
> |
least 3 real arguments, the first triplet is an additional |
| 1113 |
> |
diffuse reflectance for the front side. At least 6 real |
| 1114 |
> |
arguments adds diffuse reflectance to the rear side of the |
| 1115 |
> |
surface. If there are 9 real arguments, the final triplet |
| 1116 |
> |
will be taken as an additional diffuse transmittance. All |
| 1117 |
> |
diffuse components as well as the non-diffuse transmission |
| 1118 |
> |
are modified by patterns applied to this material. The |
| 1119 |
> |
non-diffuse reflection from either side are unaffected. |
| 1120 |
> |
Textures perturb the effective surface normal in the usual |
| 1121 |
> |
way. |
| 1122 |
|
<p> |
| 1123 |
< |
The surface normal of this type is not altered to face the incoming ray, |
| 1124 |
< |
so the front and back BSDF reflections may differ. |
| 1125 |
< |
(Transmission is identical front-to-back by physical law.) |
| 1126 |
< |
If back visibility is turned off during rendering and there is no |
| 1127 |
< |
transmission or back-side reflection, only then the surface will be |
| 1128 |
< |
invisible from behind. |
| 1129 |
< |
Unlike other data-driven material types, the BSDF type is fully |
| 1130 |
< |
supported and all parts of the distribution are properly sampled. |
| 1123 |
> |
The surface normal of this type is not altered to face the |
| 1124 |
> |
incoming ray, so the front and back BSDF reflections may |
| 1125 |
> |
differ. (Transmission is identical front-to-back by physical |
| 1126 |
> |
law.) If back visibility is turned off during rendering and |
| 1127 |
> |
there is no transmission or back-side reflection, only then |
| 1128 |
> |
the surface will be invisible from behind. Unlike other |
| 1129 |
> |
data-driven material types, the BSDF type is fully supported |
| 1130 |
> |
and all parts of the distribution are properly sampled. |
| 1131 |
|
<p> |
| 1132 |
|
|
| 1133 |
|
<dt> |
